Switching device



w. H. FRANK swncmne DEVICE Filed May 51, 1950 May 31, 1932.

INVENTOR.

A TTORNEYS.

21 2mm fifflafl BY JAM; A MM If Z2 34 l5 Patented May 31, 1932 UNITED STATES PATENT ol-"Flca WILLIAM H. FRANK, or DETROIT, MICHIGAN, ASSIGNOR To BULLDOG nn'nomrditizitiii,

UcTscoMPANY, or DETROIT, MICHIGAN, A CORPORATION or wEsT vmerma-yfi' SWITCHING DEVICE Application filed May 3 1,

This invention relates to fused switching devices and more particularly to devices useful in connection with panel boards made up of units such as are disclosed in the application of H. J. L. Frank, Serial No. 358,343, filed April 8, 1929.

In the application referred to there is disclosed a panel board made up of a number of units, each of which includes a receptacle fixed to the panel board and connected to the bus bars and a removable fused plug adapted to mate With the receptacle.

In Fig. 1 of the said application is disclosed a single branch unit, that is to say, a unit which leads current from a single bus bar thru a single fuse into a single cable terminal, while in Fig. 23 of the same application there is disclosed a double branch unit, one which leads current from two bus bars through two separate and independent fuses to two separate and independent cables.

It sometimes becomes necessary to substitute a single branch unit for a double branch unit and with devices of said application, this was accomplished by removing both the receptacle and the plug of a double branch unit from the panel, and substituting therefor the corresponding parts of a single branch unit.

Such substitution necessitating the removal of a fixed receptacle, was found objection able, and therefore, it is an object of this invention to provide means for converting the double branch unit of Fig. 23 into a single branch unit, without removing the fixed portion thereof from the panel board, such change being effected by slight alterations of the connections within the fixed receptacle and by utilizing a novel form of removable plug, one which has contacts corresponding to the contacts used on the double branch removable receptacle, but which receives a single fuse of large capacity, similar to the fuse used on the single branch unit.

It will be observed that a change from a double branch unit to a single branch unit is usually madewhen it is desired to replace two circuits each of which is of small capacity with a sin le unit of large capacity.

Further, it will e observed that since the 1930. Serial No. 458,198.

contacts of the double branch units of Fig; 23 have been designed to conduct currents of small capacity, whereas the contacts of the single branch unit of Fig. 1 have been designed for currents of large capacity, that, therefore, in converting a double branch unit to a single branch unit, care must be taken to connect the parts in such a manner that the contacts thereon are not overloaded and accordingly, an object of this invention is a unit wherein the parts are so connected that the contacts conduct currents no greater than those for which they were originally designed, even though the contacts be used on a single branch, this being accomplished by connecting the contacts-of each pair in multiple, the pairs themselves being connected in series with the remaining parts of the device, namely, the fuse clips, the bus bar, the cable terminal, etc.

A further object is a receptacle which, when connected with properly designed plugs is readily convertible from a double branch receptacle to a single branch receptacle and vice versa.

A still further object is a novel form of plug, one which is adapted to cooperate with a double branch receptacle to connect the same into a single branch receptacle.

A still further object is a novel method of converting a double branch unit to a single branch unit, one that includes the step of connecting certain contacts in multiple with each other, the parts thus formed be ing connected in series with the load.

Still other objects will readily occur to those skilled in the art upon reference to the following description and the accompanying drawings in which Fig. 1 shows in section an embodiment 'of the invention.

Fi 2 is a bottom plan view of the removable member of Fig. 1.

Fig. 3 is a phantom view of the device.

Fig. 4 is a schematic view of the wiring of the device.

Referring to the drawings, F ig. 1 shows a cup shaped block 10 having on the bottom thereof a bus bar terminal 11, cable terminals 12 and a plurality of contacts 13, 14, 15 and 16, the outer pair of contacts 13 and 16 being connected to cable terminals 12, the inner pair of contacts 14 and 15 being connected to each other and to the terminal 11 by strip 17 which in turn is connected to the bus bar 18 when the device is in operation.

It will be observed that the construction thus far described is identical with the construction disclosed in Fig. 23 of the application referred to and thus far forms no part of the present invention.

For cooperation with the receptacle 10 when a single branch unit is desired, there is provided a plug member 20 having thereon a plurality of contacts 21, 22, 23, and 24, adapted to mate with contacts 13, 14, 15 and 16 of the receptacle, respectively. There is also provided on the plug 20 a pair of fuse clips 27 and 28 (Fig. 2) connected to contacts 21 and 23 and receiving and supporting a fuse 30, the capacity of the latter being governed by the load conditions.

Further, contacts 22 and 23 are formed as part of one copper member, they being connected to each other by the short copper strap 33. Contacts 21 and 24 are connected to each other by a strap 34, which of course, is spaced from strap 33, and fuse clips 27 so as to be insulated therefrom.

There is also provided in the receptacle 10 for single branch use only a jumper or strap 31 connecting contacts 13 and 16 to each other, strap 31 being removable so that receptacle 10 may be used as a double branch receptacle if desired.

Furthermore, cable 32, leading to the load, has an end disposed within the receptacle 10 and is connected to a cable terminal 12 in a well known manner.

In the double branch use of the device there are two cables, each of which is connected to a cable terminal 12, but in the single branch use only one of the cable terminals 12 is connected to a cable 32, the other being idle.

The single branch operation of the device will readily be observed from the foregoing and from Figs. 3 and 4. y

Current of a capacity equal to load conditions leads from the bus bar 18 to strap 17 from where it runs thru two parallel paths to fuse 30, going thru the latter, and then running again in two parallel paths to cable terminal 12 and out thru cable 32. The paths may be indicated as follows:

and 23 are in multiple and 13 and 16 are in multiple, but at the same time, each air of contacts is in series with each other pair, the fuse 30, and with the terminal 12. In this manner contacts such as those disclosed may aeeaaev be of a capacity large enough to conduct only one half of the current conducted through the fuse. In other words, contacts 14 and 15 having been designed for double branch use only, may be used for single branch circuits Without fear of breakdown.

Further, insofar as receptacle 10 is concerned, the change from double branch use to single branch use is comparatively simple, the only change being the connection of contacts 13 and 16 to each other through the removable jumper 31, and the elimination of one cable 32.

Now having described the invention and the preferred embodiment thereof, it is to be understood that the said invention is to be limited, not to the specific details herein set forth, but only by the scope of the claims which follow:

1. A fused switching device comprising mating sections, each of which is provided with a plurality of contacts adapted to mate with contacts provided on the other, a bus bar, a fuse, and a cable connected to separated contacts on said sections, said bus bar and cable, being of acurrent carrying capacity at least as large as that of the fuse, said contacts being of a current carrying capacity equal to only a fraction of the capacity of said fuse, and being connected in parallel so that together their capacity is at least as great as that of the fuse and whereby they need carry a current of no larger capacity than that for which they were designed.

2. A fused switching device comprising mating sections, each of which is provided with a plurality of contacts adapted to mate with similarly disposed contacts provided on the other of said sections, a bus terminal, a

cable terminal, and a pair of fuse clips con-,

nected to each other in series through said mating contacts, the latter being connected to each other in parallel pairs which in turn are connected in series with said terminals and fuse clips.

3. A fused switching device comprising "mating sections, each of which is provided with a plurality of contacts adapted to mate with similarly disposed contacts provided on the other of said sections, a bus terminal, a cable terminal, and a pair of fuse clips connected to each other in series through pairs of said contacts, eachof said pairs including contacts arran ed in multiple or parallel connection, whereby the current carrying ca acity of each of said contacts need be on y a fraction of the current carrying capacity of said fuse clips.

4. In a fiised switching device, a fuse and a plurality of pairs of contacts, the fuse and said pairs being connected in-series with one another, the contacts ofeach pair being connected to each other in multiple, whereby each contact carries only a fraction of the current carried by the fuse.

5. In a switching device, a plurality of contact pairs connected to one another in series, the contacts of each pair being connected to each other in multiple, whereby each contact carries only a fraction of the current carried by each pair.

6. In a switching device, an outer pair of contacts and an inner pair, the contacts of the latter pair being connected to each other and removable means connecting said outer contacts to each other.

7. In a switching. device, an outer pair of contacts and an inner pair, the contacts of each pair being connected to each other, and

a fuse connecting one of said inner contacts to one of said outer contacts.

8. In a fused switching device, mating members each having thereon an outer pair of contacts and an inner pair of contacts,

all of said outer contacts being connected to each other and all of said inner contacts being connected to each other, and a fuse connecting an outer contact to an inner con- "tact.

9. In a fused switching device, mating members each having thereon an outer pair of contacts and an inner pair of contacts, all of said outer contacts being connected to each other and all of said inner contacts being connected to each other, a bus bar connected to an inner contact, a cable connected to an outer contact, and a fuse connecting an outer contact with an inner contact.

10. In combination with an elongated molded receptacle of insulation having a pair of end contacts therein, and a pair of center contacts, an elongated removable head for closing said receptacle and having an end contact engaging the receptacle end contact, and also having a center contact engaging the receptacle center contact, and a fuse carried by said head and electrically connecting the head contacts.

11. In combination with an elongated 5 molded receptacle of insulating material having two separate pairs of contacts therein spaced to cooperate with the contacts of a plurality of similar short fuse-carrying heads adapted to be disposed and received in said receptacle and together to form a cover therefor, a long head of the same length as the receptacle and dimensioned to fit therein and to form a complete cover therefor, the long head having two contacts spaced thereon to mate with contacts of different pairs of receptacle contacts.

12. In combination with an elongated molded receptacle having two pairs of contacts therein, each pair including a center contact and an end contact, a head of the length of the receptacle and having contacts spaced to mate with contacts of difi'erent pairs of receptacle contacts.

WILLIAM H. FRANK. o5 

